1. Field of the Invention
The present invention relates to an apparatus and system to automatically transfer fuel between separated portions of a fuel tank through a siphon action device which is primed by the evacuation of air and vapor by means of fuel flowing through an aspirator.
2. Description of the Relevant Art
In vehicles, a fuel tank configuration of two separated interior portions is often desirable. For example, a dual tank with a general saddle like configuration is often used on truck type vehicles. The tank has two separate and relatively deep side portions which can be connected by a shallower mid portion. This configuration is also desirable for sports type vehicles in which the vertical dimension is very limited. This tank configuration provides a space or channel between the two tank portions for a drive shaft or exhaust tubes, for example. In this configuration, fuel cannot flow by means of gravity between the two deep portions of the fuel tank. When fuel is extracted from only one tank portion, the fuel level in the other portion does not decrease. Resultantly, the weight of the two tanks is unequal. A solution is to provide a fuel intake and perhaps separate pumps in both portions of the fuel tank. But, this is a costly and complex solution.
Another solution to the aforedescribed problem is to provide a cross-over passage located near the bottom of the two tank portions. However, this practically defeats the advantage of providing the channel between the tank portions. It also increases the possibility of leaks.
Another solution is to provide a special fuel pump in the tank which operates when needed to transfer fuel from one side of the tank to the other thus maintaining the level in the two tanks. This is a complex and costly solution.
The subject invention provides apparatus to siphon fuel automatically from one side of the tank to the other. When the engine is operating, siphon action is initiated by purging the siphon of air and/or fuel vapors by the flow of fuel through the engine fuel system. Specifically, an aspirator evacuates air and fuel vapor as fuel passes through a venturi passage.
The use of a siphon initiated by a pump is old. An example is found in U.S. Pat. No. 431,542 in which a siphon is utilized to transfer liquid from one body of water to another. The pump is utilized to initiate siphon action by withdrawal of air from the upper portion of the siphon.
U.S. Pat. No. 1,472,428 discloses another siphon used to transfer liquid from one body to another and utilizes a pump to withdraw air from the high point in the siphon.
U.S. Pat. No. 3,021,855 discloses a saddle shaped fuel tank with separate right and left-hand tank portions. The left and right-hand tank portions are connected by a siphon apparatus. The siphon's inlet end in one tank has a one-way check valve to allow fuel flow into the siphon but not out. During operation of the associated vehicle, surges in liquid fuel in the one tank forces liquid into the siphon and the check valve prevents reverse flow out of the siphon. Successive fuel surges fills the siphon which may then begin to transfer liquid for the purpose of equalizing fuel levels.
U.S. Pat. No. 2,530,817 discloses another saddle shaped fuel tank with right and left-hand portions. Fuel is withdrawn from both the right and left-hand tanks through dual inlets which are commonly connected to a main fuel line leading to the engine.